Liaohe Oilfield Conventional Mud Density High Temperature And Large Temperature Difference Water System Research

With further exploration and development of oil&gas, there has been a gradual increase of the deep and ultra-deep wells in Liaohe oilfield. Both Xing buried hill reservoir and Ma buried hill reservoir exist some complicated factors in Liaohe oilfield, for example deep-seated reservoir, high bottomhole temperature, which lead to one-time up-return long interval isolation, the difference in temperature between the top and the bottom of the interval isolation, the slurry appear easily to be retarded or super-retarded at the top of the interval isolation. The phnomenon will influence cementing quality, so it is necessary to develop high temperature difference technique for the slurry system. The screening and propertical measurements of the retarder, fluid loss, meanwhile, based on the close packing and grain composition theory, the high performance cement slurry system has been developed with DRB-1S as strengthening agent. Influences of the admixture and the additive on the slurry comprehensive performance are mearsured by such as Static Strength Analyzer, Cement Hydration Analyzer, SEM, XRD, and so on.The results of experiment showed that retarder DRH-200L has a good linear relationship among addition, test temperature and the slurry thickening time. Fluid loss DRF-120L has a good linear relationship among addition, test temperature and slurry filtration. Retarding effect of the additives control the slurry thickening time by delaying hydration reaction rate of the slurry and have slight effect on the later slurry hydration and the early compressive strength development at the low temperatrue. The cement slurry system with DRB-1S of15%～20%(percentage by the cement weight) poses that a good slurry sedimentary stability, the low permeability and good compactness of Cement Pastes, compressive strength at the top of the interval isolation is over10MPa/24h, long-term compressive strength has no recession. A set of the meeting construction requirements with the bottom-hole static temperature130～165℃(the bottom-hole circulating temperature110-140℃), the temperature difference is80℃between the top and the bottom of the interval isolation, adjustable thickening time, good comprehensive performance conventional density cement slurry system has been developed through tackling key problems. This system is successfully applied in the intermediate casing Φ177.80mm of the Shen308well with these slurries are performed with100%acceptable quality and95%excellent quality. It provides scientific, reasonable technical support for application and extension of the high temperature difference slurry system.